System and method for optimizing the strength and orientation of the inductive field of a hearing aid compatible device

ABSTRACT

A system and method provides optimization of the strength and orientation of the inductive field of a hearing aid compatible (“HAC”) device, relative to a telecoil in a user&#39;s hearing aid. One aspect provides control of the drive level of a transmitting telecoil contained in the HAC device. Other aspects provide steering of the inductive field of the device by using a telecoil array and controlling the amplitude or phase of the signals transmitted by each telecoil in the array to create a composite field. Another aspect provides a plurality of transmitting telecoils arranged such that each telecoil has a different orientation, and a plurality of switches for controlling which transmitting telecoil is active. The user may then select the telecoil having a preferred orientation. Another aspect allows a transmitting telecoil to be physically oriented to an optimal position by embedding the telecoil in a substantially spherical element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of pending U.S. patent application Ser.No. 10/932,859, filed Sep. 2, 2004, which is hereby incorporated byreference in its entirety for all purposes.

BACKGROUND OF THE INVENTION

A. Field of Invention

This invention relates to hearing aid compatible devices providinginductive coupling of an audio signal to a hearing aid having atelecoil. More particularly, the invention relates to systems andmethods for optimizing the strength and orientation of the inductivefield of a hearing aid compatible device.

B. Background and Description of Related Art

Hearing aids typically use a small microphone and amplifier to pick upsound and amplify it for persons with hearing related disabilities.However, this arrangement can cause feedback when a telephone's earpieceis placed up to the wearer's ear. Additionally, the presence ofbackground noise affects the speech comprehension of people with partialhearing much more adversely than that of people with normal hearing.People with partial hearing thus require a high signal-to-noise ratio tooptimize their speech discrimination.

A hearing aid telecoil is a small, tightly wrapped piece of wire that,when activated, picks up the voice signal from an inductive field thatis emitted from hearing aid compatible (HAC) devices, such astelephones. Such inductive fields may be generated by voice-coil typespeakers, or transmitting telecoils contained in the device. Thus,telecoil-equipped hearing aids are able to bypass background noise, andprevent the phenomenon of feedback.

However, nearby electromagnetic interference. (EMI) may also be pickedup by the telecoil, creating interference with the desired voice signal.For example, power transformers, fluorescent lighting, trains and theoperation of digital wireless telephones can cause EMI that can bepicked up by telecoils.

For example, with respect to digital wireless phones, the EMI may becaused by several sources. One such source is the actual digital radiofrequency (RF) transmission of the communication signal. This pulsingsignal appears to induce continually varying current in the small wiresof the hearing aid. Another source of EMI is extraneous radiation fromthe wireless phone's battery, components and wiring. For instance, in atime-sharing, multiplex network, such as a TDMA or GSM network, the RFtransmitter of the phone turns on and off at the rate of multiplexing,which typically falls in the audio range. The heavy current drawn by theRF transmitter causes any conductors supplying current to thetransmitter to radiate this inductive EMI. Additionally, many othercomponents of the phone, such as the backlight for the display, thedisplay itself, and the keypad, utilize strobing techniques thatgenerate EMI.

One potential solution to overcoming the EMI is to boost the desiredinductive signal of the HAC device to a level that overpowers the EMI.If the inductive field of the device is strong, the telecoil can be usedwith relatively low amplification of the received signal and, thus,relatively low amplification of any EMI. However, If the inductive fieldis comparatively weak, the amplification of the signal, and, thus, anyEMI, needs to be increased to obtain an adequate signal. Furthercomplicating the problem, varying amounts of EMI may be present in theenvironment, such that the inductive signal level required to overcomethe EMI cannot be predetermined.

Still further, the generation of the boosted inductive signal creates apower drain on HAG device that is proportional to the level of theboosted signal. This power drain will shorten the operating time of HAGdevices having a “power budget”, such as battery powered wirelesstelephones. Thus, generating a larger signal will significantly reducethe length of time that the HAG device can operate, whereas a weakersignal may be adequate to overcome the EMI.

Thus, there is a need for a system and method for optimizing thestrength of the inductive field of a hearing aid compatible device thatis strong enough to overpower ambient EMI, yet having minimal powerdrain on the device's battery.

Additionally, certain classes of hearing aids have an issue withreorientation, or shifting, of the telecoil during the manufacturingprocess. More specifically, ITC (In The Canal) and CIC (Completely Inthe Canal) hearing aid classes are manufactured using techniquesallowing most or all of the hearing aid electronics to be molded into aunit that fits into the ear canal. However, in doing so the telecoil canwind up in virtually any position. Optimal coupling of the inductivesignal into the telecoil occurs when the signal field is parallel to thetelecoil. Thus, the user may have to twist the HAC device around until a“sweet spot” is found, often resulting in a position of the device thatis not optimal for its operation.

Thus, there is also need for a system and method for optimizing theorientation of the inductive field of a hearing aid compatible devicefor coupling the inductive signal into the telecoil.

SUMMARY OF THE INVENTION

The system and method of the present invention solves these needs, andothers, by optimizing the strength and orientation of the inductivefield of a hearing aid compatible device for efficient and effectivecoupling of the field with a hearing aid having a telecoil.

The invention is for a telecoil management system to optimize theinductive field strength for the user's preference and environmentalconditions. The management system could be part of the hardware andsoftware of a wireless telephone, for example. The drive level to thetelecoil will be controlled by a drive level control circuit and userinterface. This will allow the user to set the level of magneticcoupling at a level needed to match their specific needs, If the deviceis battery powered, the power that would have been expended on unneededinductive field strength can then be used to extend the operating timeof the device.

The invention also includes a means for electronic or mechanicalreorientation of the magnetic field from the phone to allow a hearingaid user to select the optimal orientation to match the orientation of atelecoil contained in the hearing aid. This will improve the usersatisfaction experience. The ability to reorient the device's inductivefield could be accomplished via the following means: by controlling theamplitude or phase of signals to each of several telecoils to create asteerable composite field, by selection of one of several coils arrangedsuch that each telecoil has a different orientation, or by physicalorientation of a transmitting telecoil to the desired orientation.

According to one aspect of the invention, a system for optimizing thedrive level of the inductive signal of a hearing aid compatible deviceincludes a user input device for signaling a change in the drive levelof the inductive signal, and a control device that is in communicationwith the user input device. In operation, the control device receivesdrive level signaling from the user input device, and processes thedrive level signaling to produce a gain signal and field strengthinformation. The system also includes a display device for displayingthe field strength information so as to provide a user with a visualindication of the drive level of the inductive signal and to therebyassist the user in selecting a desired drive level optimized for theuser's preference. The display device is in communication with thecontrol device. Still further, the system has an amplifier device thatis in communication with the control device. In operation, the amplifierdevice receives an audio signal, and amplifies the audio signal based onthe gain signal. Lastly, the system has a transmitting telecoil fortransmitting the amplified audio signal as an inductive signal. Thetransmitting telecoil is in communication with the amplifier device.Thus, the system transmits an inductive signal optimized for the user'spreference.

The system may also have a speaker and a switch, where the switch ispositioned between the amplifier device and the telecoil input to allowthe switching of the amplified audio signal to either the telecoil orthe speaker. The switch may also allow switching of the amplified audiosignal to both the telecoil and the speaker.

The user input device may have an increase input, a decrease input, anda signal output. In operation, the user input device then converts arequest for a change in the drive level of the inductive signal from theincrease input or the decrease input into increase signaling or decreasesignaling, respectively, at the signal output. The user input devicecould be, for example, a keypad on a wireless phone, where the increaseinput is an up button and the decrease input is a down button.

The control device could have a microprocessor for performing theoperations described.

According to another aspect of the invention, a system for optimizingthe orientation of the inductive field of a hearing aid compatibledevice includes a user input device for signaling a change in theorientation of the inductive field, and a control device that is incommunication with the user input. In operation, the control device ofthis aspect receives orientation signaling from the user input, andprocesses the orientation signaling to produce a first gain signal, asecond gain signal, and field orientation information. This system alsohas a display device for displaying the field orientation information soas to provide a user with a visual indication of the orientationcorresponding to the orientation signaling and to thereby assist theuser in selecting orientation signaling producing a desired orientation.The display device is in communication with the control device. Thissystem further has a first amplifier and a second amplifier, with eachamplifier being in communication with the control device. In operation,each amplifier receives an audio signal and amplifies the audio signalbased on the first gain signal and the second gain signal, respectively,to produce a first amplified audio signal and a second amplified audiosignal, respectively. The system further has a first transmittingtelecoil for transmitting the first amplified audio signal and a secondtransmitting telecoil for transmitting the second amplified audiosignal. The telecoils are in communication with the respectiveamplifiers, and the second telecoil is positioned substantiallyorthogonal to the first telecoil. The system produces a composite fieldhaving an orientation determined by the amplified audio signaltransmitted by each of the telecoils.

The system of this aspect of the invention may also have a thirdamplifier in communication with the control device, and a thirdtransmitting telecoil in communication with the third amplifier, withthe third telecoil positioned substantially orthogonal to both the firstand second telecoils. In operation, the control device further processesthe orientation signaling to produce a third gain signal. The thirdamplifier receives the audio signal and amplifies it based on the thirdgain signal to produce a third amplified audio signal. Then, the thirdtelecoil transmits the third amplified audio signal, which produces acomposite signal along with the signals transmitted by the first andsecond telecoils. The resulting composite signal is steerable in threedimensions.

In one configuration of the system, each of the telecoils has an end inclose proximity to a common end of each of the other telecoils. Inanother configuration, each of the telecoils has its middle section inproximity to the middle section of each of the other telecoils.

The system of this aspect of the invention may further have a fourthamplifier in communication with the control device. In thisconfiguration, the control device is further operative to receiveoverall drive level signaling from the user input, and process theoverall drive level signaling into an overall gain signal. The fourthamplifier can then receive an audio source signal, and amplify the audiosource signal based on the overall gain control signal to produce theaudio signal received by the first, second and third amplifiers.

More specifically, the user input device may have a joystick devicehaving activation contacts and a signal output, where the activationcontacts are operative to indicate up/down and left/right user inputsignaling. The joystick device may thus operate to apply the user inputsignaling at the signal output.

Again, the control device of the system may have a microprocessor. Thedisplay device may have an LCD screen.

Using this system, one method of orientation control signaling includesreceiving separate increase/decrease signaling for each telecoil. Usingthis method, the processing of the orientation signaling may include thesteps of: determining if the orientation signaling is for the first,second or third telecoil; determining if the orientation signaling isfor an increase or decrease in the selected telecoil; and increasing ordecreasing the gain signal for the selected telecoil.

Another method of orientation control signaling includes receivingsignaling to steer the composite field left/right or up/down. Using thismethod, the processing of the orientation signaling may include thesteps of: determining if the orientation signaling is for left/rightcontrol or up/down control; if the orientation signaling is forleft/right control, determining if the orientation signaling is for leftor right control, and increasing or decreasing the gain signal for theselected telecoil; and if the orientation signaling is for up/downcontrol, determining if the orientation signaling is for up or downcontrol, and increasing or decreasing the gain signal for the selectedtelecoil.

According to yet another aspect of the invention, a system foroptimizing the orientation of the inductive field of a hearing aidcompatible device includes: a user input device for signaling a changein the orientation of said inductive field; a control device being incommunication with said user input; a display device in communicationwith the control device; a first phase control device and a second phasecontrol device also being in communication with the control device, andfirst and second transmitting telecoils in communication with thecorresponding phase control devices. The second transmitting telecoil ispositioned substantially orthogonal to, and spatially separated from thefirst telecoil. In operation, the control device of this system receivesorientation signaling from the user input, and processes the orientationsignaling to produce a first phase signal, a second phase signal, andfield orientation information. The display device displays the fieldorientation information, for the reasons described in the earlieraspects of the invention. Each of the phase control devices receives anaudio signal and controls the phase of the audio signal based on thefirst phase signal and the second phase signal, respectively, to producea first phase-shifted audio signal and a second phase-shifted audiosignal. The first transmitting telecoil transmits the firstphase-shifted audio signal and the second transmitting telecoiltransmits the second phase-shifted audio signal, to thereby produce acomposite field having an orientation determined by the phase-shiftedaudio signal transmitted by each of the telecoils.

The system of this aspect of the invention may also have a third phasecontrol device in communication with the control device, and a thirdtransmitting telecoil in communication with the third amplifier, withthe third telecoil positioned substantially orthogonal to both the firstand second telecoils. In operation, the control device further processesthe orientation signaling to produce a third phase signal. The thirdphase control device receives the audio signal and controls the phase ofthe signal based on the third phase signal to produce a thirdphase-shifted audio signal. Then, the third transmitting telecoiltransmits the third phase-shifted audio signal, which produces acomposite signal along with the signals transmitted by the first andsecond telecoils. Again, the resultant composite signal is steerable inthree dimensions.

The user input device could have a joystick device with activationcontacts and a signal output, as described above. The joystick devicemay then operate to apply user input signaling at the signal output.

Other possible details of this system include use of a microprocessor asthe control device, or a part thereof, and use of an LCD screen in thedisplay device.

According to still yet another aspect of the invention, a system foroptimizing the orientation of the inductive field of a hearing aidcompatible device includes a plurality of transmitting telecoilsarranged such that each telecoil has a different orientation, and aplurality of switches. Each of the switches has an audio signal inputand a switch signal output. Additionally, each switch signal output isoperatively connected to a different transmitting telecoil, such thatswitching the audio signal to a different telecoil will produce aninductive field having a different orientation. In operation, eachswitch receives an audio signal at the audio signal input, and switchesthe audio signal to the corresponding switch signal output based on theuser's selection of a telecoil having an optimum orientation. Thus, theorientation of the inductive field may be optimized by selecting thetransmitting telecoil that best matches the orientation of a telecoilcontained in a user's hearing aid.

The system could further include: a user input device for signaling achange in the orientation of the inductive field; a control device incommunication with the user input device, and a display device incommunication with the control device. Additionally, each switch couldalso have a switch control input that is in communication with thecontrol device. In operation, the control device would receiveorientation signaling from the user input device, and process theorientation signaling to produce a switch control signal and telecoilselection information. The display device would display the telecoilselection information so as to provide a user with a visual indicationof the orientation corresponding to the orientation signaling and tothereby assist the user in selecting orientation signaling producing adesired orientation. Each switch would receive the switch control signaland switches the audio signal based on the switch control signal.

Other possible details of this system could include: use of a joystickwith the user input device; use of a microprocessor as the controldevice, or a part thereof; and use of an LCD screen in the displaydevice.

According to even a further aspect of the invention, another system foroptimizing the orientation of the inductive field of a hearing aidcompatible device includes a substantially spherical element including,embedded therein, an inductive field producing telecoil operativelyconnected to an audio signal source, and a semi-spherical enclosure. Thesubstantially spherical element is received partially in thesemi-spherical enclosure and is rotatable with respect to thesemi-spherical enclosure so as to vary coupling between the telecoil anda hearing aid to thereby enable optimizing of the orientation of theinductive field of the telecoil. The substantially spherical element maybe a ball.

Additionally, the system of this aspect could further include aretaining ring, where the retaining ring engages the semi-sphericalenclosure to prevent the ball from falling from the semi-sphericalenclosure. The retaining ring could have an edge and at least one tabpositioned on the edge, and the semi-spherical enclosure could have atleast one slot for receiving the retaining ring tab. Thus, the retainingring could engage the semi-spherical enclosure by placing the retainingring in the semi-spherical enclosure and rotating the ring.

In one configuration, the system could have flexible leads extendingbetween the telecoil and the audio signal source. In this configuration,the ball could further have tabs positioned to prevent rotation of theball to less than 180 degrees.

In another configuration, the ball further could have a pair of slidecontacts connected to the telecoil. The semi-spherical enclosure couldthen have a pair of movable contact strips and a pair of stationarycontact strips. The movable contact strips could then be in contact withthe slide contacts, the stationary contact strips could be in contactwith the movable contact strips, and the stationary contact strips couldbe in communication with the audio signal source, such that the ballcould rotate with respect to the semi-spherical enclosure whilemaintaining continuous contact between the telecoil and the audio signalsource.

Further, the system of this aspect of the invention could have a lockingdevice to allow the substantially spherical element to be secured in afixed position.

Thus, a method for providing optimized orientation of the inductivefield of a hearing aid compatible device relative to a hearing aid usingsuch a system could include the following steps: (i) orienting therotatable ball containing the transmitting telecoil in a selectedorientation; (ii) coupling the inductive field of the transmittingtelecoil to a hearing aid; (iii) determining if the orientation of therotatable ball produces optimal coupling between the telecoil and thehearing aid; and (iv) if the coupling produced is not optimal, repeatingstep (i) to provide a new orientation and repeating steps (ii) and(iii).

The method of this aspect of the invention could further include thesteps of: unlocking a locking device on the rotatable ball prior to step(I); and when coupling is optimal, relocking the locking device on therotatable ball in order to maintain the optimal orientation of thetelecoil and its corresponding inductive field.

Thus, the various aspects of the invention provide optimization of thestrength and orientation of the inductive field of a hearing aidcompatible device. However, the invention is not limited to thepreceding summary and will be better understood by reference to thefollowing detailed description and the appended drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of the environment of a system for optimizingthe drive level of the inductive signal of a hearing aid compatibledevice.

FIG. 2 is a view of a representative hearing aid compatible deviceincorporating such a system.

FIG. 3 is a diagram of such a system.

FIG. 4 is a flow diagram of a method utilizing such a system.

FIG. 5 is a block diagram of the environment of a system of optimizingthe orientation of the inductive field of a hearing aid compatibledevice.

FIG. 6 is a diagram of two transmitting telecoils having separateinductive fields.

FIG. 7 is a diagram of two transmitting telecoils having a compositeinductive field.

FIG. 8A is a top view of a three-dimensional substantially orthogonaltelecoil array.

FIG. 8B is a front view of the telecoil array of FIG. 8A.

FIG. 8C is a side view of the telecoil array of FIG. 8A.

FIG. 9A is a top view of a different three-dimensional substantiallyorthogonal telecoil array.

FIG. 9B is a front view of the telecoil array of FIG. 9A.

FIG. 9C is a side view of the telecoil array of FIG. 9A.

FIG. 10 is a view of a display device showing a graphical representationof the gain signals for three telecoils.

FIG. 11 is a view of an alternate display device showing a graphicalrepresentation of the relative field strength of a telecoil array.

FIG. 12A is a perspective view of a user input device for use with asystem for optimizing the orientation of the inductive field of ahearing aid compatible device.

FIG. 12B is a side view of the user input device of FIG. 12A.

FIG. 12C is a top view of the user input device of FIG. 12A, furtherhaving a directional ring covering the activation contacts.

FIG. 13 is a diagram of a system for optimizing the orientation of theinductive field of a hearing aid compatible device.

FIG. 14 is a flow diagram of a method utilizing the system of FIG. 13.

FIG. 15 is a flow diagram of the steps involved in processingorientation signaling in an exemplary absolute level control scenario.

FIG. 16 is a flow diagram of the steps involved in processingorientation signaling in an exemplary differential level controlscenario.

FIG. 17 is a diagram of an alternate system for optimizing theorientation of the inductive field of a hearing aid compatible device.

FIG. 18A is a side view of an array of telecoils for the alternatesystem for optimizing the orientation of the inductive field of ahearing aid compatible device of FIG. 17.

FIG. 18B is a top view of the array of telecoils of FIG. 18A.

FIG. 19 is a flow diagram of a method utilizing the alternate system ofFIG. 17.

FIG. 20 is a diagram of yet another alternate system for optimizing theorientation of the inductive field of a hearing aid compatible device.

FIG. 21A is a front view of a telecoil array for the alternate system ofFIG. 20.

FIG. 21B is a side view of the telecoil array of FIG. 21A.

FIG. 21C is a bottom view of the telecoil array of FIG. 21A.

FIG. 22A is a front view of another telecoil array for the alternatesystem of FIG. 20.

FIG. 22B is a side view of the telecoil array of FIG. 22A.

FIG. 23A is a front view of yet another telecoil array for the alternatesystem of FIG. 20.

FIG. 23B is a side view of the telecoil array of FIG. 23A.

FIG. 24 is a view of a representative hearing aid compatible deviceincorporating the alternate system of FIG. 20.

FIG. 25 is a diagram of an implementation of the alternate system ofFIG. 20 utilizing manual switches.

FIG. 26 is a flow diagram of a method utilizing the system of FIG. 20.

FIG. 27 is a view of a representative hearing aid compatible deviceincorporating yet another alternate system for optimizing theorientation of the inductive field of a hearing aid compatible device.

FIG. 28 is a detail drawing of a rotatable ball having a telecoil foruse with the alternate system of FIG. 27.

FIG. 29 is a sectional view of the rotatable ball only, taken throughsection line A-A of FIG. 27, showing one operative connection of thetelecoil.

FIG. 30 is a partial sectional view of the HAG device and rotatableball, taken through section line A-A of FIG. 27, showing anotheroperative connection of the telecoil.

FIG. 31 is a top view of a retaining ring for use with the alternatesystem of FIG. 27.

FIG. 32 is a top view of a semi-spherical enclosure having contactstrips for use with an embodiment having another operative connection ofthe telecoil of the alternate system of FIG. 27.

FIG. 33 is a bottom view of a rotatable ball for use with the embodimenthaving the operative connection shown in FIG. 32.

FIG. 34 is a flow diagram of a method utilizing the system of FIG. 27.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Drive Level Optimization

As shown in FIG. 1, an exemplary system 100 for optimizing the drivelevel of the inductive signal of a hearing aid compatible (HAC) deviceworks in conjunction with a transmitting telecoil 102 to transform anaudio 104 signal into an inductive signal for transmission to a hearingaid equipped 106 with a receiving telecoil 108.

FIG. 2 shows such an exemplary system as might be incorporated into aHAC device 110 such as a wireless telephone. Other HAC devices thatmight utilize this system include wireline phones, cordless phones, andpersonal entertainment devices such as radios, stereos, CD players, MP3players, etc. Such a HAC device may have a user input device 112, suchas a keypad having an up button and a down button, and a display device114, such as an LCD display. In operation, the user might access thesystem through a menu system in the phone with the assistance of a menubutton. Upon calling up the system, the display device 114 may present agraphical representation of the current drive level of the system. Theuser may then use the user input device 112 to signal either an increaseor decrease in the drive level. The system will then display the reviseddrive level on the display device 114.

As shown in greater detail in FIG. 3, an exemplary system 100 foroptimizing the drive level of the inductive signal of a hearing aidcompatible (HAC) device includes: a user input device 112; a controldevice 116; a display device 114; an amplifier device 118; and atransmitting telecoil 102.

The user input device 112 is used to signal a request for a change inthe drive level of the inductive signal of the hearing aid compatibledevice. Therefore, the user input device 112 typically has at least anincrease input 120, a decrease input 122, and a signal output 124. Theincrease input 120 and decrease input 122 could be, for example, buttonson a wireless phone labeled “up” and “down” or otherwise. The userindicates a desire to increase the drive level of the HAC device byactivating the increase input 120. If additional increases to evenhigher drive levels are desired, the user may repeat activation of theincrease input a number of times, or just hold the increase input in anactivated position, until the desired drive level is reached. Likewise,the user may indicate a desire to decrease the drive level of the HACdevice by activating the decrease input 122 in a like manner tooperation of the increase input.

The user input device 112 is operative to convert the user inputs intoincrease or decrease signaling at the signal output 124.

The control device 116, such as a microprocessor, refers generically toan electronic circuit which performs arithmetic, logic and controloperations with the assistance of internal memory. The control device116 has a user input interface 126, a display device interface 128, anda gain signal output 130. The control device 116 is in communicationwith the user input device 112 through the user input interface 126. Inuse, the control device 116 is operative to receive drive levelsignaling from the user input device 112 indicating the user's desire toeither increase or decrease the drive level of the inductive signal ofthe HAC device. The control device 116 then processes the drive levelsignaling into a gain signal and outputs the gain signal at the gainsignal output 130. Additionally, the control device 116 also processesthe gain signal into field strength information and outputs the fieldstrength information at the display device interface 128.

The display device 114 is in communication with the control device 116through the display device interface 128. The display device 114provides a graphic representation of the field strength informationreceived from the control device 116, which the user can use as an aidin setting the drive level of the system.

The amplifier device 118 can be an amplifier having an audio signalinput 160, a gain control input 162 and an audio signal output 164. Theamplifier device 118 will then amplify an audio signal present at theaudio signal input 160 by an amount determined by a gain signal presentat the gain control input 162. The gain control input 162 is incommunication with the control device gain signal output 130. In use,the amplifier device 118 is operative to receive an audio signal at theaudio signal input 160, receive a gain signal from the control device atthe gain control input 162, amplify the audio signal based on the gainsignal, and output the amplified signal at the audio signal output 164.

The audio signal output 164 may contain a switch 174, either manual orelectronic in nature, to allow the switching of the amplified audiosignal to either, or both, inductive or speaker mode of operation. Suchswitch 174 via control lead 172 may be under control of control device116 which further receives user input from user input device 112 anddisplays said status on display device 114. Such switch 174 would couplethe output of amplifier 118 to a speaker 176 and/or the telecoil 102.Alternatively, separate amplifiers may be utilized for the acoustic andinductive output modes of operation each being optimized for itsspecific mode. In this implementation, a similar switch would beutilized to selectively switch the input signals to either or both ofthe dedicated amplifiers.

It should be noted that the user input device 112, control device 116,display device 114, amplifier device 118, and speaker 176 may already beexisting items contained within the HAC device, such as are found inwireless phones.

As shown in FIG. 4, a method 200 of optimizing the drive level of theinductive signal of a hearing aid compatible device includes the stepsof: 202 receiving an audio signal at an audio signal input; 204receiving drive level signaling from a user input device; 206 processingthe drive level signaling into a gain signal; 208 processing said gainsignal into field strength information; 210 outputting said fieldstrength information to a display device; 212 amplifying said audiosignal based on said gain signal; and 214 outputting said amplifiedaudio signal to a transmitting telecoil. Additionally, the method 200could further include the step of 216 outputting said amplified audiosignal to a speaker.

B. Inductive Field Orientation Optimization

If the telecoil in the hearing aid is aligned in space so that itsmagnetic axis is parallel to the magnetic axis of a transmittingtelecoil and the distance between them is minimized, the maximumtransfer of energy will occur. Even if the space between the telecoilsis maintained and the orientation between them is changed, the couplingof energy will diminish until there will be no coupling of energy whenthe magnetic axis of the telecoils are at right angles to each other.Thus, these exemplary embodiments provide structure and techniques toallow user re-orientation of the magnetic axis of the telecoil ortelecoils in the HAC device to be more parallel to the magnetic axis ofthe hearing aid telecoil.

Thus, as shown in FIG. 5, an exemplary system 300 for optimizing theorientation of the inductive field of a HAC device transforms an audiosignal 304 into an inductive signal for transmission over a“transmitting telecoil” 302 aligned with a receiving telecoil 308 of ahearing aid 306. As explained below, the “transmitting telecoil” 302 maybe either: 1) an actual telecoil either selected or physicallymanipulated to have the desired orientation; or 2) an arrangement ofmultiple telecoils creating a resultant field or virtual telecoil havingthe desired orientation. Thus, optimizing the orientation of theinductive field of a HAC device produces effective and efficientcoupling between the “transmitting telecoil” 302 and the receivingtelecoil 308. This allows the user to use the HAC device without havingto twist it around until a “sweet spot” is found. Additionally,optimizing the orientation of the inductive field of the HAC deviceallows the drive level of the resultant signal to also be optimized.

1. 3-D Orthogonal Telecoil Array Amplitude Steering

One embodiment of such an exemplary system 400, shown in FIG. 13,involves arranging a number of telecoils in a 3-D orthogonal array, andsteering the resultant inductive field by varying the amplitude of thesignal to each telecoil to create a composite inductive field having thedesired orientation and magnitude.

FIG. 6 shows a first transmitting telecoil 424 and a second transmittingtelecoil 426 spaced from and positioned substantially orthogonal to thefirst telecoil. Each telecoil creates its own separate inductive field,as shown by the illustrative flux lines 425, 427. The inductive fieldgenerated by each telecoil is substantially parallel to the longitudinalaxis of the telecoil, except at the ends of the telecoil where the fluxlines curve inward to meet each other. If the telecoils are separated byan adequate distance, the inductive fields will exist relativelyindependent from each other. However, as shown in FIG. 7, if thetelecoils 424, 426 are placed in closer proximity while still beingsubstantially orthogonal to each other, the inductive fields will mergeinto a composite field, having flux lines substantially parallel to avirtual axis of a virtual telecoil 402. In the example shown, equalsignals are sent to both telecoils, resulting in a composite signalhaving a virtual axis substantially 45 degrees from each of thetransmitting telecoils. By varying the signal strength between thetelecoils, the virtual axis of the composite signal can be repositionedor steered in the plane of the telecoils. Thus, FIG. 7 shows anexemplary embodiment of a 2-D telecoil array having a first transmittingtelecoil 424 and a second transmitting telecoil 426.

FIGS. 8A, 8B and 8C show an exemplary embodiment of a 3-D telecoil arrayhaving a first transmitting telecoil 424, a second transmitting telecoil426, and a third transmitting telecoil 428, where the second telecoil426 is positioned substantially orthogonal to the first telecoil 424 andwhere the third telecoil 428 is positioned substantially orthogonal toboth the first telecoil 424 and the second telecoil 426. Additionally,FIGS. 8A, 8B and 8C show each of the telecoils having an end in closeproximity to a common end of each of the other telecoils, thus forming asubstantially orthogonal telecoil array in three dimensions. Theaddition of the third telecoil 428 to the array allows steering of thevirtual axis of the composite signal in three dimensions around thearray by varying the signal strength between the telecoils. It should benoted that the telecoil array shown in FIGS. 8A, 8B and 8C could bereoriented such that the telecoils meet at a point either toward theuser or away from the user.

An alternate arrangement of a 3-D orthogonal telecoil array is shown inFIGS. 9A, 98 and 9C, where the telecoils 424, 426, 428 are positionedwith their middle sections in proximity, creating a similar steerablecomposite signal.

FIG. 10 shows a display device 414 showing a potential display that auser might utilize in conjunction with a 3-D orthogonal telecoil array,as described, in order to steer the resultant composite signal. In FIG.10, each vertical bar represents the signal strength applied to aseparate telecoil. Alternately, FIG. 11 shows another potential displaydevice 414 showing a display where the horizontal bars represent adifferential signal level applied to steer the composite fieldleft/right or up/down.

Such displays would be used with a user input device 412, such as thejoystick type device as shown in FIGS. 12A, 12B and 12C, to make changesto the signal strength levels of each telecoil. FIG. 12A shows ajoystick type user input device 412 having activation contacts 413. FIG.12B shows a side view of the joystick type user input device 412, havingactivation contacts 413. FIG. 12C shows a top view of the joystick typeuser input device 412 having a directional ring 415 covering theactivation contacts. Thus, the user input device 412 will be able tocontrol either the absolute levels to the telecoils or differentiallevels to the telecoils, either which will allow steerage of thecomposite pattern.

As shown in greater detail in FIG. 13, an exemplary system 400 foroptimizing the orientation of the inductive field of a HAC deviceincludes: a user input device 412; a control device 416; a displaydevice 414; a first amplifier device 418; a second amplifier device 420;a third amplifier device 422; a first transmitting telecoil 424; asecond transmitting telecoil 426; and a third transmitting telecoil 428.Optionally, the system may also have a fourth amplifier device 423, asshown.

The user input device 412 is used to signal a request for a change inthe orientation of the inductive field. The user input device 412 mayhave a mechanism for selecting one of the telecoils and indicatingwhether the signal level applied to that telecoil should be increased ordecreased. Alternatively, the user input device may have a mechanism forselecting whether the composite field should be shifted left/right orup/down, and indication of how much the field should be shifted in theselected direction. The user input device 412 also has a signal output434 such that the user input signaling is applied at the signal output434.

A representative input device 412 is a joystick type device as discussedabove. Such joystick type devices have become very common on wirelessphones. This design makes use of much that is already available on suchwireless phones. Other than the additional audio amplifiers andtelecoils there is little hardware that will be needed to be added. Theadditional load that this embodiment will place on the microprocessor,memory, and display of such wireless phones are trivial.

A representative control device 416 is a microprocessor such is verycommonly used in almost all modern wireless phones. Thus, the term“control device” refers generically to an electronic circuit whichperforms arithmetic, logic and control operations with the assistance ofinternal memory. The control device 416 has a user input interface 450,a display device interface 452, a first gain signal output 454, a secondgain signal output 456, and a third gain signal output 458. The controldevice 416 is in communication with the user input device 412 throughthe user input interface 450. In use, the control device 416 isoperative to receive orientation signaling from the user input device412 indicating the user's desire to change the orientation of theinductive field of the HAC device. The control device 416 can thenprocess the orientation signaling into a first gain signal, a secondgain signal, a third gain signal, and field orientation displayinformation. The field orientation display information could be the datarequired to generate either of the potential displays shown in FIG. 10or 11, as described above. Then, the microprocessor 416 outputs thefirst gain signal at the first gain signal output 454, the second gainsignal at the second gain signal output 456, the third gain signal atthe third gain signal output 458, and the field orientation displayinformation at the display device interface 452. In practice, the userwill likely use an iterative process of adjusting the field orientation,placing the HAC device up to his ear/hearing aid to try out the setting,and then making further adjustments to achieve an optimized orientation.

It should be noted that, while the control device and the representativesystem 400 of FIG. 13 are described and shown as having three telecoils424, 426, 428, the exemplary system would also have utility with onlytwo telecoils to create a composite inductive field, as described above.Additionally, one of skill in the art will understand that theprinciples of the invention may also be applied to other systems havingmore than three telecoils arranged to create a steerable compositeinductive field.

The display device 414 is in communication with the control device 416through the display device interface 452. The display device 414provides a graphical representation of the field orientation displayinformation received from the control device 416, which the user can useas an aid in setting the orientation of the inductive field of thesystem, as described above.

A representative display device is an LCD display, such as is found onmany modern wireless phones. The intent is that the telecoil settingswill be one of the menu items selectable on the wireless phone. Onceactivated, it will display the setting parameters on the phone's displayuntil they are accepted by the user, and he exits that section of themenu.

Each of the amplifiers 418, 420, 422 has an input for an audio signal,an input for receiving a gain signal for determining the amount that theamplifier will amplify the audio signal, and an output for the amplifiedsignal. Thus, the first amplifier 418 has a first audio signal input470, a first gain control input 472 and a first signal output 474, withthe first gain control input 472 in communication with the first gainsignal output 454 of the control device 416. Likewise, the secondamplifier 420 has a second audio signal input 476, a second gain controlinput 478 and a second signal output 480, with the second gain controlinput 478 in communication with the second gain signal output 456 of thecontrol device 416. Finally, the third amplifier 422 has a third audiosignal input 482, a third gain control input 484 and a third signaloutput 486, with the third gain control input 484 in communication withthe third gain signal output 458 of the control device 416.

A representative amplifier that might be used in such a system is acommon LM-386-type amplifier. Other amplifiers having equivalentfunctionality could certainly be substituted without undueexperimentation. Further, the amplifier functionality also may beintegrated with other devices into a multi-function integrated circuit,as is known.

Each of the first amplifier 418, the second amplifier 420 and the thirdamplifier 422 is operative to receive a common audio signal at therespective audio signal input 470, 476, 482, receive a gain signal atthe respective gain control input 472, 478, 484, amplify the audiosignal based on the respective gain signal, and output the amplifiedaudio signal at the respective signal output 474, 480, 486.

Each of the first telecoil 424, the second telecoil 426 and the thirdtelecoil 428 is operatively connected to the signal output 474, 480, 486of the respective amplifier. The second telecoil 426 is positionedsubstantially orthogonal to the first telecoil 424. Further, the thirdtelecoil 428 is positioned substantially orthogonal to both the firsttelecoil 424 and the second telecoil 426, such that a compositeinductive field will be created by the 3-D orthogonal telecoil array.

A representative telecoil that might be used in the system is commonlyknown within the hearing aid industry, but can loosely be described as asmall coil of wire wrapped around a core with the core material usuallybeing composed of a ferrite based material.

As mentioned, the system may also optionally have a fourth amplifierdevice 423 that can be integrated into the system 400 to control theoverall volume or drive level of the system, as discussed above in thedescription of the system for optimizing the drive level of theinductive signal. In this configuration, the fourth amplifier device 423is positioned between the audio signal and the audio signal inputs 470,476, 482 of each of the first amplifier, the second amplifier and thethird amplifier. The user input device 412 can then be used to signal arequest for a change in the overall drive level of the inductive signalto the control device 416 much as is done with a volume control. Thecontrol device 416 will process this drive level signaling into anoverall gain signal and communicate this information to a gain controlinput 490 on the fourth amplifier device 423. The fourth amplifierdevice 423 will then control the level of the common signal that isinput into the other amplifiers, and, thus, the relative output level ofthe other amplifiers.

Thus, as shown in FIG. 14, a method 500 for optimizing the orientationof the inductive field of a hearing aid compatible device using such asystem would include the steps of: 502 receiving an audio signal at anaudio signal input; 504 receiving orientation signaling from a userinput; 506 processing the orientation signaling into a first gainsignal, a second gain signal, a third gain signal, and field orientationdisplay information; 510 outputting the field strength information to adisplay device; 512 amplifying said audio signal based on the first gainsignal, the second gain signal and the third gain signal into a firstamplified audio signal, a second amplified audio signal and a thirdamplified audio signal, respectively; and 514 outputting the firstamplified audio signal, the second amplified audio signal and the thirdamplified audio signal to a first transmitting telecoil, a secondtransmitting telecoil and a third transmitting telecoil, respectively.

FIGS. 15 and 16 provide additional detail regarding the steps involvedin processing the orientation signaling in an exemplary absolute levelcontrol scenario 516 and in an exemplary differential level controlscenario 518, respectively. For instance, in the absolute level controlscenario 516 (FIG. 15), the first step 520 is determining if theorientation signaling is for the X, Y or Z telecoil. The next step 522is determining if the orientation signaling is for an increase ordecrease in the level of the selected X, Y or Z telecoil. The next step524 is then either decreasing or increasing the gain signal to theselected telecoil. In the differential level control scenario 518 (FIG.16), the first step 530 is determining if the orientation signaling isfor left/right control or for up/down control. If the orientationsignaling is for left/right control, the next step 532 is determining ifthe orientation signaling is for left or right control. If theorientation signaling is for up/down control, the next step 534 isdetermining if the orientation signaling is for up or down control.Depending on the results of the preceding steps, the next step 536 is toincrease and decrease X, Y and Z amps control to implement the change.

2. 3-D Orthogonal Telecoil Array Phase Steering

As shown in FIG. 17, an alternate system 600 for steering the compositefield of a 3-D orthogonal telecoil array is to utilize phase controldevices instead of the amplifiers described above. Such a system has auser input device 612, a control device 616, a display device 614, afirst phase control device 618, a second phase control device 620, athird phase control device 622, a first transmitting telecoil 624, asecond transmitting telecoil 626 and a third transmitting telecoil 628.

In this configuration, the user input device 612 is again used to signala request for a change in the orientation of the inductive field. Thisrequest signal is communicated to the control device 616 which processesthe orientation into first, second and third phase signals, and fieldorientation display information. The composite magnetic field can beshifted in different directions by introducing different delays to thesignals exciting each of the telecoils.

The control device 616 has a user input interface 650, a display deviceinterface 652, a first phase signal output 654, a second phase signaloutput 656, and a third phase signal output 658. The control device 616is in communication with the user input device 612 through the userinput interface 650. In use, the control device 616 is operative toreceive orientation signaling from the user input device 612 indicatingthe user's desire to change the orientation of the inductive field ofthe HAC device. The control device 616 can then process the orientationsignaling into a first phase signal, a second phase signal, a thirdphase signal, and field orientation display information by computing thephase-shifts necessary to produce the desired magnetic pattern. Then,the control device 616 outputs the first phase signal at the first phasesignal output 654, the second phase signal at the second phase signaloutput 656, the third phase signal at the third phase signal output 658,and the field orientation display information at the display deviceinterface 652.

Each of the phase control devices has an audio signal input 670, 676,682 for an audio signal, a phase control input 672, 678, 684 forreceiving the phase signal, and a signal output 674, 680, 686 for thephase-shifted signal. Each phase control device is operative to receivethe audio signal and delay or phase-shift the signal by an amount basedon the phase signal received at the phase control input. Thus, the firstphase control device 618 has a first audio signal input 670, a firstphase control input 672 and a first signal output 674, with the firstphase control input 672 in communication with the first phase signaloutput 654 of the control device 616. Likewise, the second phase controldevice 620 has a second audio signal input 676, a second phase controlinput 678 and a second signal output 680, with the second phase controlinput 678 in communication with the second phase signal output 656 ofthe control device 616. Finally, the third phase control device 622 hasa third audio signal input 682, a third phase control input 684 and athird signal output 686, with the third phase control input 684 incommunication with the third phase signal output 658 of the controldevice 616.

A representative phase control device is a MX609 integrated circuit,manufactured by MX.COM, Inc. The MX609 integrated circuit is a voicecodec that is used to convert analog speech to digital which can then bedelayed in the digital domain by storing them in memory until thedesired delay time has expired and then converting the digital bits backinto analog voice. Since a wireless phone already has a voice codec init, it may be possible to piggyback this functionality onto it. Asimilar codec, the CMX639, is made by Consumer Microcircuits Limited. Atotally integrated system on a chip is a MAD4868A, manufactured byMicronas GmbH.

Each of the first telecoil 624, the second telecoil 626 and the thirdtelecoil 628 is operatively connected to the signal output 674, 680, 686of the respective phase control device. Further, as discussed above andshown in FIGS. 18A and 18B, the telecoils may be arranged in a 3-D,substantially orthogonal array with spatial separation, or alternatelymay be arranged in a 2-D linear array such that a composite inductivefield will be created. FIG. 18A is a side view of, and FIG. 18B is a topview of a 3-D, substantially orthogonal array as might be used with theexemplary phase steering system. The telecoils are still oriented on thesame three axis as shown previously; however, they have greater physicalseparation. This is necessary in order to form beam patterns with thedelays.

Thus, as shown in FIG. 19, a method 700 for optimizing the orientationof the inductive field of a hearing aid compatible device using such asystem would include the steps of: 702 receiving an audio signal at anaudio signal input; 704 receiving orientation signaling from a userinput; 706 processing said orientation signaling into a first phasesignal, a second phase signal, a third phase signal, and fieldorientation display information; 710 outputting said field strengthinformation to a display device; 712 phase-shifting said audio signalbased on said first phase signal, said second phase signal and saidthird phase signal into a first phase-shifted audio signal, a secondphase-shifted audio signal and a third phase-shifted audio signal,respectively; and 714 outputting said first phase-shifted audio signal,said second phase-shifted audio signal and said third phase-shiftedaudio signal to a first transmitting telecoil, a second transmittingtelecoil and a third transmitting telecoil, respectively.

3. Switched Telecoil Array

FIG. 20 shows another exemplary embodiment for a system 800 foroptimizing the orientation of the inductive field of a hearing aidcompatible device. The system 800 utilizes multiple telecoils in anarray, arranged such that each telecoil has a different orientation,allowing the user to select the telecoil that best matches theorientation of the hearing aid telecoil.

FIGS. 21A, 21B and 21C show the front, side and bottom views of anexemplary array containing multiple telecoils. The array shown containsfive telecoils 820, 822, 824, 826, 828. Alternatively, a 3-D orthogonalarray could be utilized, such as described above. Still further, anynumber of telecoils could be used with a variety of orientations.

Additional illustrative examples could entail four telecoils, as shownin FIGS. 22A, 22B, 23A and 23B. FIGS. 22A and 22B are front and sideviews of an array containing four telecoils 820, 822, 824, 828. FIGS.23A and 23B are front and side views of another array containing fourtelecoils 820, 822, 824, 828.

FIG. 24 shows a HAC device 810 that may incorporate such an exemplarysystem, such as a wireless telephone. Such a HAC device may have a userinput device 812, such as a keypad or a joystick pad, as shown, and adisplay device 814, such as an LCD display. Again, in operation the usermight access the system through a menu system with the assistance of amenu button. Upon calling up the system, the display device 814 maypresent a graphical representation of the currently selected telecoil,or another representation of the current orientation of the inductivefield of the system. The user may then use the user input device 812 toselect another telecoil in the array, or, in other words, to change theorientation of the inductive field of the system.

Returning now to FIG. 20, an exemplary system 800 for optimizing theorientation of the inductive field of a HAC device includes: a userinput device 812; a control device 816; a display device 814; aplurality of electronic switches 830, 832, 834, 836, 838; and aplurality of telecoils 820, 822, 824, 826, 828.

The user input device 812 such as a joystick-type device as describedabove, is used to signal a request for a change in the orientation ofthe inductive field through selection of whichever telecoil best matchesthe orientation of the hearing aid telecoil. Thus, the user input device812 has a mechanism for signaling a change in the orientation of theinductive field. The user input device 812 has a signal output 840,where the user input device signaling is output.

The control device 816, such as a microprocessor as described earlier,has a user input device interface 842, a display device interface 844,and a switch control interface 846. The control device 816 is incommunication with the user input device 812 through the user inputinterface 842. In use, the control device 816 is operative to receiveorientation signaling from the user input device 812 indicating theuser's desire to change the orientation of the inductive field of theHAC device 810, which in this case is accomplished through switching theaudio signal to a different telecoil in the array. The control device816 can then process the orientation signaling into a switch controlsignal for switching the audio signal to the selected telecoil.Additionally, the control device 816 processes the orientation signalinginto telecoil selection display information for providing a visualfeedback to the user of the particular telecoil selected. Then, thecontrol device 816 outputs the switch control signal to the switchcontrol interface 846, and outputs the telecoil selection displayinformation at the display device interface 844.

The display device 814 is in communication with the control device 816through the display device interface 844. The display device 814, suchas an LCD display as described earlier, provides a graphicalrepresentation of the telecoil selection display information receivedfrom the control device 816. The user can use this information as an aidin setting the orientation of the inductive field of the system 800since each telecoil 820, 822, 824, 826, 828 of the array has a differentorientation.

Each of the switches 830, 832, 834, 836, 838 has an audio signal input850, 852, 854, 856, 858, a switch control signal input 860, 862, 864,866, 868, and a switch signal output 870, 872, 874, 876, 878. Again fiveswitches are shown 830, 832, 834, 836, 838, corresponding to the fivetelecoils 820, 822, 824, 826, 828 shown in FIGS. 21A, 21B and 21C.However, should a different number of telecoils be utilized, acorresponding adjustment to the number of switches would also berequired. The audio signal input 850, 852, 854, 856, 858 of each switchis connected to a common audio signal source. The switch control signalinput 860, 862, 864, 866, 868 of each switch is connected to the controldevice switch control signal interface 846. The control signal input860, 862, 864, 866, 868 of each switch determines whether that switch isin an open or closed state. In the closed state, the switch will passthe audio signal through to the switch signal output. In thisembodiment, only one of the switches should typically operate in aclosed state at any given time.

Each of the telecoils 820, 822, 824, 826, 828 is operatively connectedto a switch signal output 870, 872, 874, 876, 878 of a correspondingswitch. As described above, the telecoils are arranged such that eachtelecoil has a different orientation. Thus, the orientation of theinductive field emitted by the system may be optimized by selecting thetelecoil that best matches the orientation of a telecoil contained in auser's hearing aid.

Alternatively, as shown in FIG. 25, an implementation of a switchedtelecoil array may be as simple as manual switches to select one of thetelecoils. Thus, the use of a user input device, a control device, and adisplay device would not be needed.

Thus, as shown in FIG. 26, a method 900 for optimizing the orientationof the inductive field of a HAC device using such a system would includethe steps of: 902 receiving an audio signal at an audio signal input;904 receiving orientation signaling from a user input; 906 processingsaid orientation signaling into a switch control signal, and telecoilselection display information; 910 outputting said telecoil selectioninformation to a display device; 912 switching said audio signal basedon said switch control signal; and 914 outputting said switched audiosignal to a respective transmitting telecoil.

4. Physical Orientation of Telecoil

Another alternate embodiment for a system for optimizing the orientationof the inductive field of a hearing aid compatible device utilizes asingle telecoil embedded in a ball or other substantially sphericalshaped element, such that the telecoil itself may be physically orientedfor optimal coupling with a hearing aid telecoil. FIG. 27 shows a HACdevice 1010 having a rotatable ball 1012. The rotatable ball 1012contains a telecoil 1014, as best shown in FIG. 28 and in the sectionalviews (taken through section line A-A of FIG. 27) of FIGS. 29-30. Therotatable ball 1012 may be made of a material such as plastic. As bestshown in FIG. 30, the rotatable ball 1012 containing the telecoil 1014resides within a semi-spherical enclosure 1016, or socket, that allowsthe ball to be rotated by the user's finger. The telecoil 1014 isoperatively connected to an audio signal source via flexible leads orslide contacts. Thus, the telecoil 1014 is capable of mechanicalorientation or reorientation via physical manipulation in threedimensions.

As best shown in FIGS. 30-31, a captive or retaining ring 1018 is usedto prevent the ball 1012 from falling from the semi-spherical enclosure1016. Such retaining ring 1018 has tabs 1020 on its edges which matewith slots 1022 in the spherical enclosure, as shown in FIG. 32. Placingthe retaining ring 1018 in the semi-spherical enclosure 1016 androtating the ring 1018 locks it into position.

In the exemplary embodiment shown in FIG. 29, flexible leads 1024extending from the back of the ball 1012 interconnect the telecoil 1014to the audio signal source. Tabs 1026 on the back of the ball 1012 wouldprevent rotation of the ball beyond the range that could lead to stressof the flexible leads 1024 or that would be of use to the user. A bitless than 180 degrees is the maximum rotation that would be of practicaluse.

As shown in FIG. 27, a locking device 1028 would allow the ball to besecured in a fixed position once the optimal position was obtained.

In another exemplary embodiment, shown in FIGS. 30, 32 and 33, thetelecoil 1014 in the ball 1012 is connected to the audio signal sourcevia a set of slide contacts 1030 on the back of the ball that mate withmovable contact strips 1032 within the spherical enclosure 1016. Theslide contacts 1030 slide on the movable contact strips 1032 to allowthe ball 1012 to rotate in a first plane. The movable contact strips1032 are separately in contact with one each respectively of a set ofstationary contact strips 1034. The set of stationary contact strips1034 allow the movable contact strips 1032 to move in placeperpendicular to the first plane. Thus the slide contacts 1030, themovable contact strips 1032, and the stationary contact strips 1034allow full rotation of the ball 1012 while maintaining continuouscontact between the telecoil 1014 and the audio signal source.

In operation, as shown in FIG. 34, a user can physically reorient thetelecoil to the optimal orientation, which, of course, is theorientation that best matches the orientation of the telecoil containedin the user's hearing aid. With manual orientation of the telecoil thiswould be an iterative process by the device's user. Thus, anotherexemplary method 1100 for optimizing the orientation of the inductivefield of a hearing aid compatible device includes the following steps:1102 unlocking a locking device on a rotatable ball containing atransmitting telecoil; 1104 rotating the ball to a different position;1106 attempting to couple the inductive field of the transmittingtelecoil into a hearing aid; 1108 determining if the new positionproduces optimal coupling; if coupling is not optimal, repeating saidsteps of 1104 rotating the ball to a different position, 1106 attemptingto couple the inductive field into a hearing aid, and 1108 determiningif the new position produces optimal coupling; and, if coupling isoptimal, 1110 relocking the locking device on the rotatable ball, inorder to maintain the optimal orientation of the telecoil and itscorresponding inductive field.

C. Conclusion

Thus, the invention provides a system and method for optimizing thestrength of the inductive field of a hearing aid compatible device, anda system and method for optimizing the orientation of the inductivefield of such a device, among other benefits and features.

One of ordinary skill in the art will recognize that additionalconfigurations are possible without departing from the teachings of theinvention or the scope of the claims which follow. This detaileddescription, and particularly the specific details of the exemplaryembodiments disclosed, is given primarily for clearness of understandingand no unnecessary limitations are to be understood therefrom, formodifications will become obvious to those skilled in the art uponreading this disclosure and may be made without departing from thespirit or scope of the claimed invention.

1. A system for optimizing the orientation of the inductive field of ahearing aid compatible device, said system comprising: a substantiallyspherical element including, embedded therein, an inductive fieldproducing telecoil operatively connected to an audio signal source; anda semi-spherical enclosure, said substantially spherical element beingreceived partially in said semi-spherical enclosure and being rotatablewith respect to said semi-spherical enclosure so as to vary couplingbetween said telecoil and a hearing aid to thereby enable optimizing ofthe orientation of the inductive field of the telecoil.
 2. The system ofclaim 1, wherein said substantially spherical element is a ball.
 3. Thesystem of claim 2, further comprising a retaining ring, said retainingring engaging said semi-spherical enclosure to prevent said ball fromfalling from said semi-spherical enclosure.
 4. The system of claim 3,wherein said retaining ring has an edge and at least one tab positionedon said edge, wherein said semi-spherical enclosure has at least oneslot for receiving said at least one retaining ring tab, said retainingring engaging said semi-spherical enclosure by placing said retainingring in said semi-spherical enclosure and rotating said ring.
 5. Thesystem of claim 2, further having flexible leads extending between saidtelecoil and said audio signal source.
 6. The system of claim 5, whereinsaid ball further has tabs positioned to prevent rotation of the ball toless than 180 degrees.
 7. The system of claim 2, wherein said ballfurther has a pair of slide contacts connected to said telecoil, whereinsaid semi-spherical enclosure has a pair of movable contact strips and apair of stationary contact strips, said movable contact strips being incontact with said slide contacts, said stationary contact strips beingin contact with said movable contact strips, and said stationary contactstrips being in communication with said audio signal source, such thatsaid ball may rotate with respect to said semi-spherical enclosure whilemaintaining continuous contact between said telecoil and said audiosignal source.
 8. The system of claim 1 further having a locking deviceto allow said substantially spherical element to be secured in a fixedposition.
 9. A method providing optimized orientation of the inductivefield of a hearing aid compatible device relative to a hearing aid, saidmethod comprising the steps of: (i) orienting a rotatable ballcontaining a transmitting telecoil in a selected orientation; (ii)coupling the inductive field of said transmitting telecoil to a hearingaid; (iii) determining if the orientation of the rotatable ball producesoptimal coupling between said telecoil and said hearing aid; and (iv) ifthe coupling produced is not optimal, repeating step (i) to provide anew orientation and repeating steps (ii) and (iii).
 10. The method ofclaim 9, further including: unlocking a locking device on said rotatableball prior to step (i); and when coupling is optimal, relocking thelocking device on said rotatable ball in order to maintain the optimalorientation of the telecoil and its corresponding inductive field.